The pathogenesis of pre-invasive lesion development

The progression of pre-invasive bronchial lesions is a multifocal and multistep process. Morphological malignant transformation is driven by the accumulation of multiple genetic and epigenetic abnormalities, the rate and number of which determines the risk and rate of progression toward cancer. The field effect of mutagenesis in airways is characterised by the multifocality of the lesions. To date, no evidence has been presented for genetic alterations accumulating in a known sequence. No individual alteration is sufficient to predict the occurrence of invasive cancer in the bronchial tree.